Blanching of fruits and vegetables

Trimming, cutting, juicing, and blanching of fruits and vegetables... 

Blanching of fruits and vegetables before osmotic treatment strongly affects the course of the process. Blanching of carrots and potatoes reduces water loss and increases solids gain [73,77,80], Hence, its effect is detrimental to osmotic... 

Dorantes-Alvarez, L., Barbosa-Caanovas, G., Gutiearrez-Loa Fez, G. (2000). Blanching of fruits and vegetables using microwaves, in Barbosa-Caanovas G and Gould G, Innovations of Food Processing, Lancaster Technomic, 149-162. 

It is not uncommon to find that a treatment which enhances the stability of one quality factor causes another factor to become unacceptable. A chemical additive, such as calcium chloride, may improve the textural quality of a fruit product, but it can also produce unacceptable flavors. Blanching, to inactivate enzymes that cause darkening, destroys the fresh-like textural quality that is desired in lightly processed fruits and vegetables. 

Storage at low temperature in the dark. The autoxidation rate is thereby decreased substantially. However, in fruits and vegetables which contain the lipoxygenase enzyme, these precautions are not applicable. Food deterioration is prevented only after in activation of the enzyme by a blanching process (cf. 2.6.4). 

Most of the technological processes used in fruit and vegetable processing include washing and blanching. The decrease in the levels of pesticide residues is possible particularly in the case of pesticides that are soluble in water, or in the case of contact pesticides deposited on the plant surface that can be mechanically removed. The overall effects resulting in a reduction of pesticide residues depend on a number of factors, the most important of which are ... 

Fig. 4.3. Survey of freeze dried vegetables and fruits. Blanching time between 2 and 4 minutes (part of Table 1 from [4.11]).

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